Urea solution tank assembly

ABSTRACT

A tank for storing urea solution and a tank assembly for storing disparate fluids, such as diesel fluid and urea solution, are disclosed. The tank may further include a filler assembly and/or a sensor assembly, either of which are adapted to be connected to the tank without the use of separate fasteners, The tank assembly may include a reservoir and a sensor for automatically diverting non-conforming urea solution to the reservoir. A recess may be defined in the tank body in order to accommodate a strap for securing the tank to the frame of vehicle. The tank may include parallel sidewalls that include a projection on one and a corresponding indentation on the other in order to allow the tanks to be easily stacked during assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to commonly-assigned, U.S. provisionalapplication Ser. No. 61/012,484, filed Dec. 10, 2007 by applicantsRobert H. Versaw Jr. et al. entitled UREA SOLUTION TANK ASSEMBLY, thecomplete disclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to tanks for storing urea solution, andmore particularly to tanks that may be utilized in conjunction with aselective catalyst reduction (SCR) system that reduces the nitrogenoxide (NOx) emissions of a motorized vehicle.

Nitrogen oxides are one of the main components responsible for thegeneration of ground level ozone. They also contribute to the formationof acid rain, and have other deleterious side effects. The EnvironmentalProtection Agency (EPA) tracks the emissions of nitrogen oxides, alongwith five other common pollutants, and sets national ambient air qualitystandards for NOx. NOx are primarily generated by the burning of fuels,such as by motor vehicles, electric utilities, or other sources.

One known method of reducing the amount of NOx emissions is to utilize aselective catalyst reduction process that uses a urea solution. Forexample, in a motor vehicle, the urea solution may be injected into thehot exhaust gas flow from the engine where it reduces the NOx bytransforming it into nitrogen and water. In order to carry out theselective catalyst reduction process, urea solution must be stored andavailable for use by the SCR system.

SUMMARY OF THE INVENTION

The present invention relates to an improved container assembly forstoring the urea solution that may be used in an SCR system for reducingNOx emissions. The SCR system may be part of a motorized vehicle, or itmay be an SCR system used to reduce the NOx emissions of a stationarysource. In at least one aspect, the container assembly of the presentinvention provides an economical system for storing urea solution thatis durable enough to withstand the rigors of motorized vehicletransport, and that may be incorporated into the design of existingmotorized vehicles with little or no disruption to the vehiclemanufacturer's existing design.

According to one aspect of the present invention, a tank assembly isprovided for storing both diesel fuel and urea solution. The tankassembly includes first and second chambers and a tank positioned withinthe second chamber. The first chamber is adapted to store diesel fueland includes a first aperture for receiving diesel fuel. The secondchamber is fluidly isolated from the first chamber but shares at least afirst wall with the first chamber. The tank includes a first holeadapted to receive a urea solution which is aligned with a secondaperture defined within the second chamber. The alignment of the firsthole and second aperture allow urea solution to be delivered through thesecond aperture and the first hole into the tank.

According to another aspect of the present invention, a tank assemblyfor storing urea solution is provided. The tank assembly includes a tankhaving a first sidewall, a second sidewall, and a perimeter wall. Thesecond sidewall is spaced from the first sidewall, and the first andsecond sidewalls each generally define a first and second plane,respectively, wherein the first and second planes are parallel to eachother. The perimeter wall connects the first and second sidewallstogether. The first wall further includes an indentation having a firstshape, and the second wall includes a projection having a second shape.The second shape substantially matches the first shape such that theprojection on a first one of the tanks may be inserted into theindentation on a second one of the tanks when a plurality of the tanksare stacked on top of each other. This stacking arrangement helps resistmovement of the stacked tanks in any direction parallel to the firstplane.

According to another aspect of the present invention, a tank assembly isprovided. The tank assembly includes a tank adapted for storing ureasolution, a reservoir fluidly isolated from the tank, a sensing unit,and a switch. The tank includes an aperture for receiving urea solution.The sensing unit is positioned adjacent the aperture and adapted todetect a quality of the urea solution being delivered to the aperture.The switch is adapted to direct the urea solution to the reservoir ifthe sensing unit determines that the quality of the urea solution doesnot conform to a predetermined standard. The switch is further adaptedto allow the urea solution to enter the tank if the sensing unitdetermines the quality of the urea solution does conform to thepredetermined standard.

According to yet another aspect of the present invention, a tankassembly for storing urea solution is provided. The tank assemblyincludes a tank, an L-shaped bracket, a plurality of side brackets, anda strap. The tank includes a first sidewall, a second sidewall, and aperimeter wall. The second sidewall is spaced from the first sidewall,and the first and second sidewalls each generally define planes that areparallel to each other. The perimeter wall connects the first and secondsidewalls together. The L-shaped bracket is adapted to be secured to amotor vehicle. The side brackets are adapted to be secured to theL-shaped bracket. The strap is adapted to be secured to the sidebrackets in a recess defined in the perimeter wall of the tank. Therecess is shaped to receive a portion of the strap whereby the strap andthe recess cooperate to secure the tank to the L-shaped bracket and theside brackets.

According to still other aspects of the present invention, the tank mayinclude one or more recesses allowing it to be secured to a vehicle viaa strap, as well as a plurality of fastener holes allowing it to besecured to the vehicle via fasteners, thereby allowing the same tank tobe mounted to the vehicle in different configurations. The tank may bemade from molded plastic, and it may be positioned within an enclosuredefined by a metal front cover and a metal rear cover that are connectedtogether via a metal hoop. Alternatively, the enclosure may be designedas a two-piece structure having a first part with an integrated frontand perimeter wall that fully encompasses the molded tank on threesides, and a second part that attaches to the first part and covers thefourth side of the tank. The switch may utilize a solenoid and thereservoir into which the urea solution is directed when its quality doesnot meet a predetermined standard may be integrally molded as part ofthe tank.

The various aspects of the present invention provide an advantageousstorage solution for storing liquid catalysts, such as a urea solution.The storage solution is designed to be robust, easily manufactured, andable to be integrated into existing vehicles such that manufacturers ofvehicles will be able to implement SCR systems into their vehicles withminimal impact from the necessity of storing urea solution on thevehicle. These and other aspects of the present invention will beapparent to one skilled in the art in light of the following writtendescription and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a tank assembly according to a firstembodiment of the present invention;

FIG. 2 is a perspective, exploded view of the tank assembly of FIG. 1;

FIG. 3 is a perspective, exploded view of a bracket system of the tankassembly of FIG. 1;

FIG. 4 is a perspective view of a tank of the tank assembly of FIG. 1;

FIG. 5 is a side, elevational view of the tank of FIG. 4;

FIG. 6 is a vertical, cross-sectional view of the tank assembly of FIG.1 illustrating several interior components of the tank;

FIG. 7 is an exploded, perspective view of a filler tube assembly of thetank assembly of FIG. 1;

FIG. 8 is a perspective view of a retainer of the filler tube assemblyof FIG. 7;

FIG. 9 is an elevational view of the retainer of FIG. 8;

FIG. 10 is a close-up elevational view of the retainer of FIG. 8;

FIG. 11 is a cross-sectional view of the filler tube assembly of FIG. 7shown attached to a perimeter wall of the tank;

FIG. 11A is a plan view of the retainer of FIG. 8;

FIG. 12 is a perspective view of the tank of FIG. 1 illustrating firstand second apertures defined within the tank;

FIG. 13 is an elevational view of a shroud of the filler tube assemblyof FIG. 7;

FIG. 14 is an exploded, perspective view of a sensor unit assembly ofthe tank assembly of FIG. 1;

FIG. 15 is a perspective view of a retainer of the sensor unit assemblyof FIG. 14;

FIG. 16 is a sectional view of the sensor unit assembly of FIG. 14 shownattached to a perimeter wall of the tank;

FIG. 17 is a perspective view of a portion of a sensor unit of thesensor unit assembly of FIG. 14;

FIG. 18 is a close-up, perspective view of the retainer of FIG. 15;

FIG. 19 is a perspective view of a tank assembly according toalternative embodiment of the present invention;

FIG. 20 is a perspective, exploded view of the tank assembly of FIG. 19;

FIG. 21 is a sectional view of a filler tube assembly of the tankassembly of FIG. 19;

FIG. 22 is a perspective view of a tank assembly according to anotheralternative embodiment of the present invention;

FIG. 23 is a sectional view of the tank assembly of FIG. 22;

FIG. 24 is a perspective, exploded view of the tank assembly of FIG. 22;

FIG. 25 is a perspective view of an L-bracket;

FIG. 26 is an exploded, perspective view of an alternative filler tubeassembly;

FIG. 27 is a perspective view of a retainer of the filler tube assemblyof FIG. 26;

FIG. 28 is a sectional view of the filler tube assembly of FIG. 26 shownwith its components assembled together;

FIG. 29 is a front, elevational view of a tank according to anotherembodiment of the invention;

FIG. 30 is a side, elevational view of the tank of FIG. 29;

FIG. 31 is a sectional view of the tank of FIG. 29 taken along the lineXXXI-XXXI;

FIG. 32 is a sectional view of the tank of FIG. 30 taken along the lineXXXII-XXXII;

FIG. 33 is a side, elevational view of a tank enclosure body;

FIG. 34 is a front, elevational view of the tank enclosure body of FIG.33;

FIG. 35 is a bottom view of the tank enclosure body of FIG. 33;

FIG. 36 is a top view of the tank enclosure body of FIG. 33;

FIG. 37 is a sectional view of the tank enclosure body of FIG. 33 takenalong the line XXXVII-XXXVII in FIG. 33;

FIG. 38 is an enlarged view of the area labeled C in FIG. 33;

FIG. 39 is a side, elevational view of a tank enclosure end cap that maybe attached to the tank enclosure body of FIG. 33;

FIG. 40 is a front, elevational view of the end cap of FIG. 39;

FIG. 41 is a sectional view of the end cap of FIG. 39 taken along theline XLI-XLI of FIG. 39;

FIG. 42 is a perspective view of an alternative tank having a pluralityof fastener apertures defined therein for attaching components thereto,such as a gasket and an attachment plate for a sensor assembly;

FIG. 43 is a perspective view of a portion of an alternative sensorunit;

FIG. 44 is a plan view of a sensor attachment plate; and

FIG. 45 is a plan view of a sensor attachment plate gasket.

DETAILED DESCRIPTION OF THE INVENTION

A tank assembly 20 according to a first embodiment of the presentinvention is illustrated in FIG. 1. Tank assembly 20 includes a tank 22for storing a urea solution, a filler tube assembly 24, a sensor unitassembly 26, and a bracket system 28. Filler tube assembly 24 is adaptedto allow urea solution to be delivered to tank 22 through a firstaperture 30 (FIG. 2). Sensor assembly 26 is adapted to sense the levelof urea solution within tank 22, as well as to allow urea solution to bepumped out of tank 22 through a second aperture 32 for delivery to aselective catalyst reduction (SCR) system (not shown), which may belocated on a motorized vehicle as part of a nitrogen oxide (NOx)emission reduction system for the motorized vehicle. Alternatively, inat least one embodiment, the SCR system may be utilized to help reducethe emissions from a stationary source of NOx, and tank assembly 20 maythus be mounted in a stationary location, rather than on a motorizedvehicle. Regardless of the stationary or non-stationary aspect of thesource of NOx emissions, sensor unit assembly 26 may also be adapted toreturn unused urea solution into tank 22 through second aperture 32, aswell as others to perform additional functions, as will be discussedmore below.

When used in conjunction with a motorized vehicle, bracket system 28 maybe used to secure tank 22 to a chassis rail 34 (only a portion of whichis illustrated in FIG. 1) that is part of a frame of a motor vehicle,such as truck. Bracket system 28 is particularly suited for mounting tothe side of a truck in a location adjacent to an external diesel fueltank for the truck. Bracket system 28, in the illustrated embodiment,includes an L-shaped bracket 36, two side brackets 38, and a strap 40(FIG. 3). Side brackets 38 each include a vertical flange 42, ahorizontal flange 44, and an angled flange 46. Vertical flanges 42, inthe illustrated embodiment, each include a pair of apertures 48 thatalign with a pair of upper apertures 50 on L-shaped bracket 36. Anysuitable fastener (not shown), such as, but not limited to, screws,bolts, rivets, and the like, may be inserted through apertures 48 andupper apertures 50 in order to secure side brackets 38 to L-shapedbracket 36.

Horizontal flanges 44 of each side bracket 38 include a plurality ofapertures 52 that align with a plurality of lower apertures 54 onL-shaped bracket 36 (FIG. 3). Any suitable fasteners (not shown), suchas, but not limited to, screws, bolts, rivets, and the like, may beinserted through apertures 52 and lower apertures 54 in order to securehorizontal flanges 44 of side brackets 38 to the lower portion ofL-shaped bracket 36. As can further be seen in FIG. 3, each angledflange 46 includes at least one angled aperture 56. When bracket system28 is assembled, angled aperture 56 aligns with a strap aperture 58defined in a foot flange 59 adjacent each end of strap 40. Thisalignment allows a suitable fastener (not shown) to be inserted throughboth apertures 56 and 58 to thereby secure strap 40 to side brackets 38.Any suitable fastener may be used for this purpose, such as, but notlimited to, screws, bolts, rivets, or the like.

As can be seen more clearly in FIG. 1, when suitable fasteners havesecured side brackets 38 to L-shaped bracket 36 and strap 40 to sidebrackets 38, bracket system 28 securely encloses and rigidly constrainstank 22. This constraint is assisted by a recess 60 defined in aperimeter wall 62 of tank 22 (FIGS. 2 and 4). A head portion 64 of strap40 is shaped to have a curvature that generally matches the curvature ofrecess 60. A rubber strap 66 (FIG. 2) may be placed between the headportion 64 of strap 40 and recess 60 of tank 22. Rubber strap 66 willthus be sandwiched between head portion 64 and recess 60 and, due to itsflexible and compressible nature, reduce any vibrations that mightotherwise be transferred from strap 40 to tank 22, as well as to morefirmly secure tank 22 to bracket system 28.

Bracket system 28 firmly holds tank 22 such that there is substantiallyno movement of tank 22 within bracket system 28 when the components ofbracket system 28 are secured together. As can be seen, bracket system28 does not utilize any fasteners that pierce any portion of tank 22itself. Tank 22 can therefore be secured to bracket system 28 withoutthe use of any fasteners directly attached to, or inserted into, anyportion of tank 22. Bracket system 28 thereby enables tank 22 to besecured to a vehicle, or other suitable structure, without having todrill any holes in tank 22, or otherwise create fastener aperturestherein. Bracket system 28 may be secured to chassis rail 34 (FIGS. 1and 2) by way of any suitable fasteners (not shown) inserted through aplurality of bracket apertures 68 (FIGS. 2 and 3) defined in L-shapedbracket 36 and into chassis rail 34.

While other materials may be used, rubber strap 66 may be made ofrubber, or any other similar type material, such as plastic, orsomething else. Tank 22 is usefully constructed of a material that doesnot react with the chemical components of the urea solution which it isadapted to store, such as stainless steel or a suitable plastic, likehigh density polyethylene (HDPE), or any other suitable plasticmaterial. L-shaped bracket 36, side brackets 38, and strap 40 may alsobe made of any sufficiently strong material, such as steel, althoughother metals may be used, as well as other non-metals, plastics, and/orcomposite materials.

Tank 22, in the illustrated embodiment, includes a pair of generallyplanar sidewalls 70 a and b that are connected together by perimeterwall 62 (FIGS. 1-2 and 4). Sidewalls 70 a and b generally define planes(not shown) that are oriented in a vertical orientation when tankassembly 22 is attached to a motor vehicle. The two respective planes ofsidewalls 70 a and b are oriented generally parallel to each other and,in one embodiment, face in a direction generally perpendicular to theforward movement of the vehicle to which tank 22 may be attached. Tank22 may be positioned in other orientations, of course, when attached tomotor vehicle. Indeed, as noted above, tank 22 may, in at least oneembodiment, be used for supplying urea solution to a stationary SCRsystem, in which case it would not necessarily be mounted to a vehicleof any kind.

Sidewalls 70 a and b may be shaped differently from each other in orderto assist the stacking of multiple ones of tanks 22 on top of each otherduring storage, or for other purposes prior to assembly of tank assembly20. As can be seen more clearly from a comparison of FIGS. 1 and 4,sidewall 70 a includes a projection or bulge 72 generally in the middlearea of sidewall 70 a. In the illustrated embodiment, projection 72 hasthe general shape of the letter “D,” although it will be understood bythose skilled in the art that the shape of projection 72 can be variedfrom the “D” shape illustrated in the accompanying drawings. Sidewall 70b (FIG. 4) includes an indentation 74 that, in the illustratedembodiment, is also generally “D” shaped. Indentation 74 is shaped anddimensioned to receive projection 72 from a separate tank 22 whenmultiple tanks 22 are stacked on top of each other, or compressedtogether in a side-by-side fashion.

During the manufacture or storage of tanks 22, projections 72 andindentations 74 help prevent tanks 22 from tipping over if they arestacked to a relatively high height. The insertion of a projection 72from a first tank 22 into the indentation 74 of an adjacent tank helpsprevent slippage of each tank with respect to each other. In otherwords, the seating of projection 72 in an indentation 74 allows twoadjacent tanks 22 to fit together in a mating fashion whereby each tankis generally prevented from moving with respect to the other in anydirection that is generally parallel to the planes defined by sidewalls70 a and b. This further allows multiple tanks to maintain alignmentwith each other when stacked vertically, or arranged in a side-by-sidemanner.

As was mentioned, the shape of projections 72 and indentations 74 ofsidewalls 70 a and b can be varied from that illustrated in theaccompanying drawings. As some possible examples, an X shape, a square,a circle, or other geometric shapes may be used. Whatever shape is used,one of sidewalls 70 a and b will have a projection in that shape and theother of sidewalls 70 a and b will have an indentation that matches thechosen shape. In some instances, it may be advantageous to choose ashape that is non-symmetrical, such as the “D” shape illustrated in theaccompanying drawings. By choosing a non-symmetrical shape, it is notpossible to stack multiple ones of tanks 22 on top of each other withoutthem all having the same orientation. With the use of a symmetricalshape for projections 72 and indentations 74, it would be possible forone projection 72 of a first tank to fit into the correspondingindentation 74 of a second tank in multiple orientations. Indeed, if theshape of projections 72 and indentations 74 were circular, a projection72 could be inserted into an indentation 74 in virtually an infinitenumber of different orientations. Non-symmetrical shapes thus may offersome benefits for projections 72 and indentations 74, although it willbe understood that the present invention may be practiced withsymmetrical shapes. It will also be understood that the presentinvention may be practiced, in at least some embodiments, with noprojections 72 or indentations 74 whatsoever, in which case sidewalls 70a and b may be perfectly flat, or have other shapes.

In the illustrated embodiment, tank 22 may further include a pluralityof fastener apertures 76 defined in a plurality of center walls 78(FIGS. 4 and 5). Fastener apertures 76 are not utilized in the tankassembly 20 depicted in FIGS. 1-2, but they may be provided on tank 22for allowing tank 22 to be mounted in different configurations, as willbe described in more detail below. Generally speaking, when fastenerapertures 76 are utilized, they receive suitable fasteners, such asscrews, bolts, rivets, or the like, for mounting tank 22 to whateverstructure it is desired to mount tank 22 to. Because tank 22 may be madeof molded plastic, in one embodiment, the molding of tank 22 withfastener apertures 76 included therein allows the same tank 22 to bemounted in different configurations. This enables the same mold anddesign to be used for the tanks 22 even though they may be mounteddifferently in different situations, while adding negligible costs totank 22 in those instances where fastener apertures 76 are not utilized.

As can be seen in greater detail in FIG. 6, sidewalls 70 and perimeterwall 62 of tank 22 combine to define an interior chamber 80 inside oftank 22. Chamber 80 stores urea solution for use in an associated SCRsystem. In the illustrated embodiment, there are only two openings intochamber 80: first aperture 30 (FIG. 2) in which filler tube assembly 24is positioned, and second aperture 32, in which sensor unit assembly 26is positioned. Filler tube assembly 24, as will be described in moredetail below, provides an opening for inserting the nozzle of a ureasolution pump, thereby providing access to the inside of tank 22 foradding additional urea solution to chamber 80. Sensor unit assembly 26,as will be described in greater detail below, generally senses the levelof urea solution within chamber 80 of tank 22, provides inlet and outlettubes to which hoses may be coupled for transferring the urea solutionto the SCR system and for returning unused urea solution from the SCRsystem (such as when the motor vehicle's engine shuts off). Sensor unitassembly 26 may also provide structures for heating the urea solution tokeep it from freezing, as well as additional sensors for monitoring thequality of the urea solution.

FIG. 7 illustrates in greater detail various of the components of fillertube assembly 24. The components of filler tube assembly 24, in theembodiment illustrated in FIG. 7, attach to each other, as well as totank 22, without the use of any separate fasteners. This cuts down onthe manufacturing cost of filler tube 24 because it is easier toassemble, and there are no additional costs associated with separatefasteners. As will be discussed more below, filler tube assembly 24 canbe modified to include the use of separate fasteners, if desired.

Filler tube assembly 24 includes a retainer 82, an O-ring 84, an outerhousing 86, a reduction sleeve 88, a shroud 90, a retainer gasket 150,and a cap 92 (FIG. 7). In general, retainer 82 attaches to tank 22 in asnap-fitting manner with perimeter wall 62 of tank 22. Retainer gasket150 provides a liquid-impervious seal between retainer 82 and tank 22.O-ring 84 provides a liquid-impervious seal between shroud 90 andretainer 82. Outer housing 86 and reduction sleeve 88 cooperate todefine a filling aperture through which a urea solution dispensingnozzle may be inserted for filling chamber 80 with urea solution. Cap 92provides a way for sealing the filling aperture during the interim timeperiods between fillings of tank 22. The design and construction ofthese components will be described in greater detail below.

Turning first to retainer 82, which is illustrated in greater detail inFIGS. 8-10, it includes a tubular body portion 94 (that defines a fillertube) having a circular plate portion 96 defined at a top end of thetubular body portion. The interior of tubular body portion 94 is hollowto thereby define a channel through which urea solution and/or thenozzle of a urea solution dispensing structure may be inserted. Thisinternal channel of the tubular body portion 94 is aligned with acentral aperture 98 of circular plate portion 96. An underside 100 ofcircular plate portion 96 includes a plurality of extensions 102 thatare used to secure retainer 82 to tank 22 within first aperture 30 oftank 22. As can be seen more clearly in FIGS. 9 and 10, each extension102 includes a flexible arm 104 having an outer cam surface 106. Eachextension 102 also includes a bottom surface 110. As will be discussedin greater detail below, prong 105 is used as manufacturing assembly aidto insure an exact orientation of retainer 82 when it is attached totank 22.

The purpose of extensions 102, flexible arms 104, cam surfaces 106, andbottom surfaces 110 can be more easily understood with respect to FIG.11. Each flexible arm 104 is positioned on circular plate portion 96 ata location that will cause its respective outer cam surface 106 toengage an edge 108 (FIG. 11) of perimeter wall 62 of tank 22 as retainer82 is inserted into first aperture 30 defined in perimeter wall 62. Morespecifically, the angled nature of cam surface 106, along with theflexibility of arms 104, will cause the arms 104 to flex inwardly towardtubular body portion 94 due to the contact with edges 108 as retainer 82is inserted into first aperture 30 in an inward direction 112 (FIG. 11).This inward flexing will continue as retainer 82 is inserted in inwarddirection 112 until bottom surface 110 reaches a shoulder 114 definedadjacent edge 108 of perimeter wall 62.

When bottom surface 110 reaches shoulder 114, the resilient nature offlexible arms 104 will cause the arms 104 to spring or snap back totheir unflexed positions, which is possible because edge 108 is nolonger exerting a force against cam surfaces 106. When arms 104 snapback to their unflexed positions, retainer 82 will be prevented frombeing removed from tank 22 by the contact of bottom surface 110 of arms104 with shoulder 114 of perimeter wall 62. Retainer 82 will thus besecured to tank 22 via a snap fit that requires no separate fastenersand no fastener apertures drilled, or otherwise defined, through anyportions of perimeter wall 62 or sidewalls 70 a or b.

Retainer 82 is prevented from rotating within first aperture 30 of tank22 by way of a flexible prong 105 (FIG. 9) that fits into a cutout 107defined along the perimeter of first aperture 30 (FIG. 12). Whenretainer 82 is inserted into first aperture 30, prong 105 will not flexinwardly toward tubular body portion 94 of retainer 82 if prong 105 isnot aligned with cutout 107. Consequently, retainer 82 can only beinserted into first aperture 30 if prong 105 is aligned with cutout 107.When inserted in this manner, retainer 82 is prevented from rotatingwithin first aperture 30 due to prong 105's contact with the pair ofedges 109 defined on each end of cutout 107.

Tubular body portion 94 of retainer 82 includes an enlarged diameterregion 1 16 positioned adjacent circular plate portion 96 (FIGS. 8, 9,and 11). Enlarged diameter region 116 houses outer housing 86 andreduction sleeve 88 (FIG. 11). Outer housing 86 and reduction sleeve 88may be conventional components available commercially from ELAFLEX-GummiEhlers, GmbH, which has a principal place of business in Hamburg,Germany. Outer housing 86 and reduction sleeve 88 include a magneticstructure that may be detected by a corresponding magnetic detector on anozzle of a urea solution dispenser. Such dispensers are commerciallyavailable in Europe and may be designed to inhibit the dispensing ofurea solution until the magnetic detector detects the magnetic structureof outer housing 86 and reduction sleeve 88. This helps prevent a personfrom inadvertently dispensing urea solution into an improper tank, suchas the gasoline or diesel tank of a motor vehicle.

Further, inner sleeve 88 includes an interior channel 118 (FIG. 11)having a diameter D. Diameter D may be dimensioned such that it canreceive a specific-sized nozzle that is used for dispensingurea-solution that is different than the size of conventional nozzlesused for dispensing gasoline and/or diesel fuel. Such a specific sizewould be dependent upon the manufacturer of the urea-solution dispensingnozzle. In at least one embodiment, diameter D is smaller than thediameter of conventional gasoline and diesel dispensing nozzles, therebypreventing a person from inserting a gasoline or diesel nozzle into tank22 and inadvertently filling the tank with gasoline or diesel fuel.Diameter D may be varied to suit the particular nozzle size of whateverdispenser, or types of dispensers, that may be used to refill tank 22.

As can be more clearly seen in FIG. 11A, retainer 82 includes acruciform 99 defined inside tubular body portion 94. Cruciform 99includes first and second cross-bars 101 a and b. Cruciform 99 acts asan anti-siphon guard that helps prevent a siphon hose from beinginserted through tubular body portion 94 and into the liquid contents oftank 22.

As is illustrated more clearly in FIG. 8, retainer 82 includes acircular groove 120 defined in a top surface 122 of its circular plateportion 96. Circular groove 120 is dimensioned to receive O-ring 84.O-ring 84 is retained within circular groove 120 by shroud 90 which,when secured to retainer 82, compresses O-ring 84 such that aliquid-tight seal is formed between retainer 82 and shroud 90. O-ring 84may be made from any suitable elastomeric-type material that is able tobe compressed, that is resistant to reaction with urea-solution, andthat is capable of forming a liquid-resistant seal between shroud 90 andretainer 82.

Shroud 90 is depicted in greater detail in FIG. 13. Shroud 90 includes aplurality of feet 124 that extend downwardly from a body portion 126.Each foot 124 includes an outer angled surface 128 and an inner angledsurface 130. Feet 124 are dimensioned and spaced such that they each maybe inserted into corresponding slots 132 (FIGS. 8 and 10) defined incircular plate portion 96 of retainer 82. After feet 124 are insertedinto slots 132, shroud 90 may be rotated such that each outer angledsurface 128 comes into contact with a first surface 134 of a lip 136defined on the underside 100 of retainer 82 (FIG. 10). Feet 124 aresufficiently flexible such that continued rotation of shroud 90 willcause feet 124 to flex enough to allow outer angled surface 128 of feet124 to slide up first surface 134 of retainer 82. After outer angledsurface 128 has slid past first surface 134, feet 124 will return totheir unflexed (or less flexed) state, in which case inner angledsurface 130 of shroud 90 will contact a second surface 138 of lips 136.Due to the relatively steep angle of inner angled surface 130 and secondsurface 138, along with O-ring 84′s resistance to being compressedbetween shroud 90 and retainer 82 (which will tend to force surfaces 130and 138 together), the contact between surfaces 130 and 138 willsubstantially prevent shroud 90 from being rotated in its oppositedirection, thereby securing shroud 90 to retainer 82. Shroud 90 andretainer 82 may thus be secured together without the use of any separatefasteners.

As can be seen more clearly in FIG. 7, shroud 90 includes a pair ofslots 140 that receive corresponding projections (not shown) on anunderside of cap 92. These projections may be shaped in a conventionalmanner such that, upon rotation of cap 92 after insertion into a centralaperture 142 of shroud 90, cap 92 is releasably secured to shroud 90.The design of the projections on cap 92, along with their interactionwith shroud 90, may be the same or similar to the construction ofconventional radiator caps and the manner in which those radiator capsare releasably secured to a radiator. Other designs may also be used,such as, but not limited to, external threads on cap 92 that threadinglymate with internal threads defined within central aperture 142 of shroud90.

Sensor unit assembly 26 is depicted more clearly in FIG. 14 and includesa sensor unit 144, a cover 146, a retainer 148, and a gasket 150. Sensorunit assembly 26 is secured to tank 22 without the use of separatefasteners and/or separate holes drilled, or otherwise defined, inperimeter wall 62 of tank 22. Sensor unit assembly 26 is secured to tank22 primarily by way of retainer 148, and retainer 148 generally operatesin the same manner as retainer 82 of filler tube assembly 24, as hasbeen described above.

Retainer 148 is depicted in greater detail in FIG. 15. Retainer 148includes a plurality of extensions 152 that are generally the same asextensions 102 of retainer 82. Extensions 152 each include a flexiblearm 154 having a cam surface 156 and a bottom surface 158. When retainer148 is inserted into second aperture 32 of tank 22, cam surfaces 156engage an edge 160 of second aperture 32, which causes the flexible arms154 to flex inwardly (FIG. 16). This inward flexing continues until camsurfaces 156 reach an underside 162 of perimeter wall 62, at which pointthe flexible arms 154 snap back to their unflexed states, and bottomsurfaces 158 engage underside 162, thereby preventing retainer 148 frombeing removed from second aperture 32. Retainer 148 further includes aprong 164 that functions in the same manner as prong 105 of retainer 82.That is, prong 164 fits into a cutout 166 (FIG. 12) defined on an insideof the perimeter of second aperture 32. Prong 164 prevents retainer 148from rotating due to its contact with edges 168 of cutout 166. Gasket150 may be sandwiched between retainer 148 and an exterior surface ofperimeter wall 62, as illustrated in FIG. 16. Retainer 148 and gasket150 may thus be secured to tank 22 without the use of any separatefasteners or apertures defined in tank 22.

As can be seen more clearly in FIG. 16, cover 146 fits over acylindrical wall 170 of retainer 148. Cover 146 is held in place by atop wall 172 of sensor unit 144 that sandwiches a portion of cover 146between top wall 172 and cylindrical wall 170. Sensor unit 144, in turn,is secured to retainer 148 in a manner that is generally similar to themanner in which shroud 90 is secured to retainer 82, as has beendiscussed. That is, sensor unit 144, a portion of which is illustratedin greater detail in FIG. 17, includes a plurality of feet 174 that eachhave an outer angled surface 176 and inner angled surface 178. Feet 174are dimensioned to fit into corresponding slots 180 defined on retainer148 (FIGS. 15 and 18). After feet 174 are inserted into slot 180, sensorunit 144 may be rotated such that outer angled surfaces 176 each comeinto contact with a first surface 182 of a lip 184 defined on retainer148 (FIG. 18). Due to the flexible nature of feet 174, sensor unit 144may be further rotated until inner angled surfaces 178 of feet 174 comeinto contact with second surfaces 186 of lips 184, at which point feet174 will return to an unflexed (or less flexed) state. This return tothe unflexed state, along with the configuration of feet 174 and lips185, will secure sensor unit 144 to retainer 148 and substantiallyprevent removal therefrom. Sensor unit 144 may thus be secured toretainer 148 without the use of separate fasteners.

Sensor unit 144 may include a plurality of ports 188 (FIG. 17) that maybe in fluid communication with a plurality of tubes 190. Ports 188 maybe used for a variety of different purposes, and the number may bevaried from that illustrated. In general, one or more ports 188 may beconnected to appropriate hoses (not shown) that are in fluidcommunication with the external SCR system that utilizes the ureasolution contained within tank 22. For example, a first port 188 may beconnected to a hose that transports urea solution to the SCR system, anda second port 188 may be connected to a hose that returns unused ureasolution to tank 22. Another one or more ports 188 may be connected tohoses that are in fluid communication with the coolant fluid of themotor vehicle's engine. In such a case, the coolant may be pumpedthrough one of the ports 188, cycled through one or more of tubes 190,and returned out to a different port 188, wherein the circulation of thecoolant through tubes 190 within tank can help keep the urea solutionfrom freezing during cold temperatures.

As yet another alternative, one or more of tubes 190 may houseelectrical heating filaments that supply heat to the urea solutionwithin tank 22 to keep the urea solution from freezing during coldtemperatures. In such a case, one or more of ports 188 could beelectrically connected to the appropriate wires or cables that deliveredthe electricity to the heating elements inside tank 22. Still further,one or more of tubes 190 may house sensing equipment that determines thefluid level of the urea solution within tank 22. Such sensors would thenpass that fluid level determination information on to an appropriatelocation on the vehicle, such as the vehicle's dashboard, where a driverof the vehicle would then be provided with an indication of how muchurea solution remained within tank 22. The design and construction ofsensor unit 144 may vary substantially from that shown in theaccompanying drawings. In one embodiment, sensor unit 144 may be aconventional sensor unit commercially available from Wema Systems, whichhas a principal place of business in Laksevaag, Norway. Other types ofsensor units, of course, can be used, including ones that performadditional sensing functions, such as monitoring the quality of the ureasolution, the temperature, or any other parameter that may desirably bemeasured with respect to tank 22.

FIGS. 19 and 20 depict an alternative tank assembly 20′ according toanother aspect of the present invention. Tank assembly 20′ may beconstructed to include a number of components that are identical withcomponents of tank assembly 20. Such identical components areillustrated in FIGS. 19 and 20 with the same reference numerals as wereused with tank assembly 20. Because these components are the same, theywill not be described further. In one embodiment, the components of tankassembly 20′ that are different from tank assembly 20 are a front cover200, a rear cover 202, a hoop 204, a pair of spacers 206, and a cover208. In other embodiments, tank assembly 20′ may differ from tankassembly 20 by the addition, modification, or removal of othercomponents as well.

Front cover 200, rear cover 202, and hoop 204 (FIGS. 19-20) are sealedtogether to define a chamber in which tank 22 may be positioned. Frontcover 200, rear cover 202, and hoop 204—which may be constructed of ametal, such as, but not limited to, steel—may be secured togetherthrough the use of rivets. Other methods of sealing these componentstogether may also be used. Front cover 200, rear cover 202, and hoop 204provide protection against physical damage to tank 22, which ispositioned inside of these components.

In order to secure tank 22 and front cover 200, rear cover 202, and hoop204 to a motor vehicle, a bracket system may be used, such as thebracket system 28 discussed previously with respect to tank assembly 20.FIGS. 19 and 20 illustrate various components of bracket system 28,including L-shaped bracket 36, side brackets 38, and strap 40. In orderto accommodate the dimensional change due to the inclusion of hoop 204,spacers 206 are inserted between angled flange 46 of side brackets 38and foot flange 59 of strap 40 (as shown in FIG. 19). Spacers 206 may beconstructed of any suitable material, such as, but not limited to, anelastomeric or compressible type material that is able to generallywithstand the weather conditions to which it may be subjected to whentank assembly 20′ is attached to a motor vehicle.

One other component of tank assembly 20′ that may differ from tankassembly 20, as noted above, is the inclusion of cover 208. Cover 208 ispositioned externally to hoop 204 and is seated around shroud 90 offiller tube assembly 24′. More specifically, cover 208 fits into acircular groove 210 defined in body portion 126 of shroud 90 (FIG. 13).Cover 208 may be made of a suitably flexible material in order to allowitself to be stretched over body portion 126 until it seats itself incircular groove 210. Filler tube assembly 24′ differs from filler tubeassembly 24 in that it includes cover 208. In all other respects, fillertube assembly 24′ may be the same as filler tube assembly 24, althoughit will be understood by those skilled in the art that additionalmodifications can be made to filler tube assembly 24′ (as well as fillertube 24).

Front cover 200, rear cover 202, and hoop 204 of tank assembly 20′ mayalternatively be replaced by a two-part enclosure that includes anenclosure body 205 and an end cap 207 (FIGS. 33-41). Enclosure body 205(FIGS. 33-38) includes a sidewall 192 and a perimeter wall 194 having afirst aperture 196 and a second aperture 198 defined therein. Firstaperture 196 is positioned to align with first aperture 30 of tank 22when tank 22 is positioned inside of enclosure body 205 and end cap 207.Second aperture 198 is positioned to align with second aperture 32 oftank 22 when tank 22 is positioned inside of enclosure body 205 and endcap 207.

End cap 207 (FIGS. 39-41) includes a main wall 201 having a flange 203defined generally around the perimeter of main wall 201. Flange 203 isgenerally oriented perpendicularly to main wall 201. Flange 203 mayinclude a plurality of apertures defined therein for receiving fasteners(such as, but not limited to, rivets, screws, bolts, etc) that areinserted through perimeter wall 194 of enclosure body 205 to therebysecure enclosure body 205 to end cap 207. Alternatively, end cap 207 maybe secured to enclosure body 205 via welding, or any other suitablefastening technique. As noted, end cap 207 and enclosure body 205provide another manner of enclosing and protecting tank 22 which may beutilized in lieu of front cover 200, rear cover 202, and hoop 204. Itwill, of course, be recognized by those skilled in the art that othermethods of enclosing tank 22 may also be used in conjunction with thevarious embodiments depicted and discussed herein.

A tank assembly 20″ according to another embodiment of the presentinvention is depicted in FIG. 22. Tank assembly 20″ includes a number ofcomponents that may be the same as one or more of the componentsdescribed above with respect to tank assemblies 20 and 20′. Such commoncomponents are identified in the accompanying drawings with the samereference numerals as have been used for tank assemblies 20 and 20′, andfurther description of such components is not deemed necessary sincethey are the same components as has been previously described. It willbe understood, of course, however, that one or more of such componentscould be modified according to other embodiments of the presentinvention.

Tank assembly 20″ is constructed so as to be able to store, in additionto urea solution, another liquid. The other liquid is stored in aseparate chamber inside of tank assembly 20″ that is fluidly isolatedfrom the chamber in which the urea solution is stored. The other liquidmay be a liquid fuel for a motorized vehicle, such as gasoline or dieselfuel. In the embodiment illustrated in FIG. 22, tank assembly 20″ isconstructed in a shape that is especially suited for attachment to theside, or chassis rail, of a truck, and thus the separate chamber insideof tank assembly 20″ may be utilized for storing diesel fuel. Forpurposes of the following written description, it will be assumed thatthe other liquid stored inside tank assembly 20″ is diesel fuel,although it will be understood that this reference is only made forpurposes of describing one embodiment, and that other embodiments maystore other types of liquids.

Tank assembly 20″ includes two end plates 216 that are attached ateither end to a barrel section 218 (FIGS. 23-24). A baffle 220 ispositioned internally within barrel section 218 and divides the interiorof barrel section 218 into a first chamber 222 and a second chamber 224(FIG. 23). Baffle 220 may be secured inside barrel section 218 by way ofwelding, or any other suitable fastening means. First chamber 222 maystore diesel fuel for a truck. The size of first chamber 222 may thusvary in order to match the desired amount of fuel for a particulartruck. Barrel section 218, baffle 220, and end plates 216 may bepositioned and dimensioned such that first chamber 222 may store anysuitable amount of diesel fuel, which may vary according to the sizeand/or type of truck to which tank assembly 20″ may be attached.

Tank assembly 20″ in the embodiment illustrated in FIGS. 22-24 includesa nipple 226 and a filler tube 228 defined in barrel section 218. Fillertube 228 provides an opening for inserting a nozzle of a diesel pump sothat a person can fill first chamber 222 up with diesel fuel. The dieselfuel of first chamber 222 comes into direct contact with the interiorwalls of baffle 220, barrel section 218 (specifically that portion ofbarrel section 218 defined on the opposite side of baffle 220 as secondchamber 224), and one of end plates 216. A cap, or other structure, maybe releasably attached to filler tube 228 such that a substantiallyliquid tight seal is created over filler tube 228 when first chamber 222is not being filled. Filler tube 228 may take on a wide variety ofdifferent forms, and in at least one embodiment, may be any conventionalfiller tube used on a conventional diesel fuel tank.

Nipple 226 on tank assembly 20″ may be used to provide an outlet fromfirst chamber 222 such that diesel fuel may be pumped out of firstchamber 222 to the engine of the motor vehicle to which tank assembly20″ is attached. Nipple 226 may take on any suitable form, such as anyconventional nipple used on conventional diesel fuel tanks.

Second chamber 224 houses a urea solution tank 22 that, in theillustrated embodiment, is the same urea solution tank 22 that is usedwith tank assemblies 20 and 20′, discussed previously. Tank assembly 20″could, of course, be used with tanks configured and designed differentlythan tank 22. Tank 22, in the illustrated embodiment, includes a fillertube assembly 24′ and a sensor unit assembly 26, which may be identicalto the filler tube assembly 24′ and sensor unit assembly 26 that is usedwith tank assembly 20′, as discussed above.

Sensor unit assembly 26 of tank assembly 20″, in the embodimentillustrated in FIG. 24, is the same as sensor unit assembly 26 describedpreviously with respect to tank assemblies 20 and 20′. Morespecifically, sensor unit assembly 26 includes a sensor unit 144, acover 146, a retainer 148, and a gasket 150. These components areassembled together in the same manner as has been previously describedabove. Similarly, the components of filler tube assembly 24′ of tankassembly 20″ are assembled together in the same manner as has beendescribed previously with respect to filler tube assembly 24 andassembly 24′. Accordingly, further description of these components isnot necessary.

Tank 22 may be secured inside of second chamber 224 in a variety ofdifferent manners. In the embodiment illustrated, tank 22 is securedinside of second chamber 224 to the interior of barrel section 218 byway of a plurality of L-brackets 232, one of which is illustrated ingreater detail in FIG. 25. L-bracket 232 includes a first section 234and a second section 236 oriented at generally a right angle to firstsection 234. Fastener apertures are defined in each section 234 and 236for receiving fasteners 238, which may be bolts, screws, or othersuitable fasteners. One of fasteners 23 8, in addition to being insertedthrough L-bracket 232, is inserted through one of fastener apertures 76defined in tank 22 (FIG. 5). The other fastener 238 is inserted througha suitably aligned hole (not shown) in barrel section 218. As can beseen in FIG. 5, tank 22 in the illustrated embodiment includes fivefastener apertures 76. In this embodiment, five L-brackets withcorresponding fasteners 238 may thus be used to secure tank 22 to barrelsection 218. FIG. 23 illustrates an L-bracket 232 in the position inwhich it helps secure tank 22 to barrel section 218. The number andtypes of fasteners may, of course, be varied from that illustrateddepending upon the design considerations and/or needs of a particularapplication.

In the embodiment illustrated in FIG. 24, the end plate 216 adjacenttank 22 may be secured to barrel section 218 by way of a plurality ofrivets 240, although other types of fastening methods may alternativelybe used, such as, but not limited to, screws, bolts, self-tappingscrews, and welding. A gasket 242 may be positioned between the endplate 216 adjacent tank 22 and barrel section 218. The position ofgasket 242 when end plate 216 is secured to barrel section 218 isillustrated in FIG. 23. By positioning tank 22 inside of barrel section218 and end plates 216, tank 22 may not only be concealed from view, buttank assembly 20″ assumes a look that is substantially identical to thelook of conventional diesel fuel tanks mounted to the side of trucks.Tank assembly 20″, in the illustrated embodiment, thus provides anaesthetic advantage in that it enables a truck manufacturer to easilyincorporate a urea solution tank with minimal changes to the overalllook of the truck. Of course, tank assembly 20″ may take on other formsthan the embodiment illustrated, including forms that don't offer theaesthetic advantage of looking like a conventional diesel fuel tank.

As has been noted above, the design of filler tube assemblies 24 and 24′and sensor tube assembly 26 may be varied from that illustrated (as wellas other components of the various tank assemblies). One suchmodification of a filler tube assembly is depicted in FIGS. 26-28.Filler tube assembly 24″ of FIGS. 26-28 differs from filler tubeassembly 24 and 24′ described previously in that filler tube assembly24″ includes a modified retainer 82′. Filler tube assembly 24″ includesa number of components that are the same as components previouslydescribed above. These components include the same reference numerals ashave been used above, and because they operate in the same manner as hasbeen previously described, they will not be described further. Thesecomponents include cap 92, cover 208, shroud 90, O-ring 84, reductionsleeve 88, gasket 150, and outer housing 86.

Modified retainer 82′ is illustrated in greater detail in FIG. 27.Modified retainer 82′ primarily differs from retainer 82 describedpreviously in that it includes a plurality of fastener holes 252 thatare defined in plate portion 96 of retainer 82′. Further, retainer 82′does not include any extensions 102 used to secure it to tank 22.Instead, retainer 82′ is secured to tank 22 by way of suitablefasteners, such as screws, bolts, rivets, or the like, inserted throughfastener holes 252 and into corresponding holes 246 defined in perimeterwall 62 of a tank 22′ (FIG. 42). Tank 22′ differs from tank 22 in thatit includes holes 246 defined generally around the perimeter of firstand second apertures 30 and 32. Tank 22′ may also differ from tank 22 inthat it does not include cutouts 107 and/or 166 in apertures 30 and/or32.

Holes 246 may be holes having internal threads, and such internalthreads may be defined by threaded metallic threaded inserts (not shown)that are molded into tank 22 during the molding process (as noted above,tank 22, in at least one embodiment, may be constructed from a suitablemolded plastic). Retainer 82′, unlike retainer 82, is thus secured totank 22 by way of a plurality of separate fasteners. The use of theseparate fasteners obviates the need for utilizing a prong and cutoutarrangement for preventing the rotation of retainer 82′ with respect totank 22. Consequently, retainer 82′ does not include a prong 105, nor,as mentioned, does the corresponding aperture 30 into which retainer 82′is inserted into tank 22 need to have a cutout, such as cutout 107discussed previously. Holes 246, as will be discussed more below, may bearranged in a non-symmetrical manner such that the filler tube assemblyand/or the sensor assembly that is mounted via fasteners inserted intoholes 246 can only be attached in a single orientation, therebyassisting the manufacturing process and helping to prevent errors inassembly.

Gasket 150 of filler tube assembly 24″ may be positioned between anunderside 100 of plate portion 96 of modified retainer 82′ and theexterior surface of perimeter wall 62 of tank 22, as is illustrated moreclearly in FIG. 28. In some embodiments, gasket 150 may be omitted fromfiller tube assembly 24″, and in still other embodiments, additionalgaskets may be used. Indeed, fewer or greater numbers of gaskets may beused in any of the various tank assembly embodiments discussed above.Still further, in one embodiment, the gaskets 150 that are used invarious locations on the various tank assemblies 20, 20′, and 20″ mayall be the same. That is, they may all be constructed of the samematerial and have the same dimensions. Such uniformity reducesmanufacturing costs by allowing a single component to be used inmultiple locations for multiple purposes. In other embodiments, the sizeand/or material of gaskets 150 may vary individually in order to matchthe components they respectively interact with.

FIGS. 42-45 illustrate various components of an alternative sensor unitassembly. These components include a sensor unit 144′ (FIG. 43), asensor attachment plate 254, and a sensor attachment plate gasket 256(FIGS. 42 and 44-45). Sensor unit 144′ differs from sensor unit 144 inthe manner in which it attaches to a tank, such as tank 22′.Specifically, sensor unit 144′ attaches to tank 22′ via a plurality offasteners inserted into holes 246 of tank 22′ (FIG. 42) in a manner thatwill now be described.

As can be seen in FIG. 44, sensor attachment plate 254 includes acentral aperture 258 having a plurality of cutouts 270 defined along theperimeter of central aperture 258. Cutouts 270 are dimensioned andpositioned to receive a corresponding number of projections 272 definedon an exterior surface 274 of a cylindrical wall 276 on sensor unit 144′(FIG. 43). (It will be noted that sensor unit 144′ of FIG. 43 includesmore projections 272 than there are cutouts 270 illustrated in FIGS. 42and 44. In practice, the number of projections 272 would match thenumber and position of cutouts 270). Sensor attachment plate 254 furtherincludes a plurality of attachment holes 282 that are used to secureattachment plate 254 to tank 22′, as will be discussed more below.

Sensor attachment plate gasket 256 (FIG. 45) also includes a centralaperture 280 that has a radius greater than the radius of centralaperture 258 of attachment plate 256. Gasket further includes aplurality of attachment holes 284 that may be aligned with attachmentholes 282 of attachment plate 254. Gasket 256 fits between perimeterwall 62 of tank 22′ and attachment plate 254. Gasket 256 and attachmentplate 254 are secured to perimeter wall 62 by way of fasteners insertedthrough attachment holes 282 and 284 and into holes 246 of tank 22′. Anysuitable fastener may be used.

As was noted above, fastener holes 246 and attachment holes 282 and 284are, in one embodiment, positioned such that they are not symmetrical.That is, in the embodiment illustrated in FIGS. 42, 44, and 45, a linedrawn between each of the four holes 246 (or holes 282, and 284) wouldnot define a square, a diamond, or any other symmetrical shape. In thismanner, attachment plate 254 and gasket 256 can only be attached to tank22′ in a single orientation. If either plate 254 or gasket 256 arerotated from this single orientation, holes 246, 282, and 284 will notalign with each other, and a fastener cannot be inserted through all ofthese holes. This helps insure that sensor unit assembly 144′ isassembled onto tank 22′ in only a single, correct orientation, therebyreducing the potential for mistakes made during the manufacturing of thetank assembly. Attachment holes 246 for securing filler tube assembly24″ to tank 22′ may also be non-symmetrical in the same or similarmanner as the attachment holes 246 used for securing the sensor unitassembly to tank 22′. Thus, both the sensor unit assembly and fillertube assembly will only be able to be attached to tank 22′ in a singleorientation.

The number of holes 246, 282, and 284 can be varied from the fourillustrated, and the particular arrangement of these holes can be variedin a variety of different configurations such that a non-symmetricalconfiguration is achieved. By defining cutouts 270 in a non-symmetricalfashion, it is possible to ensure that sensor unit 144′ is mounted totank 22′ in only a single orientation. After attachment plate 254 andgasket 256 are secured to tank 22′ by way of suitable fasteners insertedthrough holes 236, 282, and 284, sensor unit 144′ is mounted to tank 22′by inserting a bottom end 278 (FIG. 43) of projections 272 into cutouts270 of sensor attachment plate 254. After projections 272 aresufficiently inserted through central aperture 258, sensor unit 144′ isrotated. This rotation causes a set of shoulders 286 (FIG. 43) to engagethe underside of attachment plate 254 and thereby prevent sensor unit144′ from being removed from tank assembly 22′. Sensor unit 144′ issubstantially prevented from rotating back to the position in whichprojections 272 are in alignment with cutouts 270 by the frictionalinteraction of projections 272 with gasket 256.

FIGS. 29-32 illustrate one of several alternative tank designs that maybe used with any of the tank assemblies discussed above. Specifically,FIGS. 29-32 illustrate a tank 22″ that includes a reservoir 260 fluidlyisolated from a chamber 80′ by an internal wall 266 (FIGS. 31-32). Tank22″, like tank 22, may be molded from a suitable plastic, and reservoir260 may be molded as an integral part of tank 22″. The general purposeof reservoir 22″ is to store urea solution that does not conform to therequirements of the SCR system to which the tank 22″ is supplying ureasolution. For example, with motor vehicle SCR systems, it has been foundthat urea solutions containing approximately 32.5% urea are well suitedfor the SCR system. Accordingly, reservoir 260 may be utilized to storeurea solution that varies from the desired concentration of urea by apredetermined amount.

Tank 22″ is adapted to work in conjunction with a sensor 262 thatdetects one or more parameters of the urea solution as a person attemptsto fill chamber 80′ with the urea solution. In other words, when aperson inserts a urea solution nozzle into a filling aperture 268,sensor 262 detects at least one quality of the urea solution that isdispensed from the nozzle. If sensor 262 detects that the quality meetsa predetermined standard (within a predetermined tolerance), then sensor262 allows the urea solution to be dispensed into chamber 80′. Incontrast, if sensor 262 detects that the urea solution has a qualitythat does not conform to the predetermined standard, it diverts theincoming urea solution to reservoir 260 via a conduit 264, which may bea hose, or any other suitable structure.

Sensors 262 may take on any suitable form, including sensors of the typemanufactured by Wema Systems, which has a principal place of business inLaksevaag, Norway. Sensor 262 may monitor the specific gravity of theurea solution, its electrical conductivity, or other factors that relateto the desired characteristics of the urea solution, includingcombinations of two or more of these factors. Sensor 262 includes aswitch (not shown), which may comprise an electrically operated solenoidthat moves a valve, or other similar structure, in order to selectivelydivert the incoming urea solution into either chamber 80′ or reservoir260. Other types of switches besides solenoids may be used.

Tank 22″ can be modified substantially from the embodiment illustratedin FIGS. 29-32. For example, tank 22″ could be modified to include anauxiliary chamber (not shown) adjacent filling aperture 268 that is influid contact with sensor 262. The auxiliary tank could be utilized totemporarily store the incoming urea solution until sensor 262 was ableto determine whether it conformed to the predetermined standards or not.Once the proper determination was made, sensor 262 would activate theswitch to divert the urea solution into the appropriate location, e.g.either to reservoir 260 or chamber 80′.

Alternatively, tank 22″ could be constructed such that sensor 262 couldonly divert the urea solution of the auxiliary chamber into chamber 80′.In such an embodiment, if sensor 262 detected that the urea solutionwithin the auxiliary chamber did not conform to the predeterminedstandard, sensor 262 would not activate any switch or valve. Instead,the urea solution would remain in the auxiliary chamber until it wasmanually drained by a person, such as through a drain plug defined in anappropriate location on the auxiliary chamber. Still other designvariations of tank assembly 22″ could be made such that it was capableof separating and storing two different types of urea solution—the firstbeing that which met one or more predetermined standards, and the secondbeing that which did not meet the one or more predetermined standards.

While several forms of the invention have been shown and described,other forms will be apparent to those skilled in the art. Therefore, itwill be understood that the embodiments shown in the drawings anddescribed above are merely for illustrative purposes, and are notintended to limit the scope of the invention as defined by the followingclaims, which are to be interpreted under the principles of patent law,including the doctrine of equivalents.

1. A tank assembly for holding both diesel fuel and urea solution, saidtank assembly comprising: a first chamber defined within said container,said first chamber being adapted to store diesel fuel; a first aperturedefined within said first chamber for receiving diesel fuel; a secondchamber defined with said container, said second chamber and said firstchamber being fluidly isolated from each other, and said first andsecond chambers sharing at least a first wall; a tank positioned withinsaid second chamber, said tank having a first hole adapted to receive aurea solution; and a second aperture defined within said second chamberwherein said second aperture is aligned with said first hole such thaturea solution can be delivered through said second aperture and saidfirst hole into said tank.
 2. The tank assembly of claim 1 wherein saidtank is made from a material different from said second chamber, andsaid tank is made from molded plastic.
 3. The tank assembly of claim 1further including: a reservoir; a sensing unit positioned adjacent saidsecond aperture, said sensing unit adapted to detect a quality of theurea solution; and a switch adapted to direct the urea solution to saidreservoir if said sensing unit determines that the quality of the ureasolution does not conform to a predetermined standard, said switchfurther adapted to allow the urea solution to enter said tank if saidsensing unit determines the quality of the urea solution does conform tothe predetermined standard.
 4. The tank assembly of claim 3 wherein saidswitch includes a solenoid that may be selectively activated in order todirect the urea solution into either said tank or said reservoir.
 5. Thetank assembly of claim 4 further including a drain plug positioned at alower region of said reservoir, said drain plug adapted to beselectively removed from said reservoir such that liquid within saidreservoir may be removed through said drain plug.
 6. The tank assemblyof claim 1 further including: a second hole in said tank; a secondaperture defined in said second chamber, said second hole and saidsecond aperture being aligned with each other; and a sensor assemblypositioned within said second hole and said second aperture, said sensorassembly adapted to detect a level of urea solution with said tank, andsaid sensor assembly further including a tube for transporting ureasolution out of said tank.
 7. The tank assembly of claim 1 wherein saidtank includes a first sidewall and a second sidewall, said first andsecond sidewalls generally each defining first and second planes,respectively, that are parallel to each other, wherein said firstsidewall includes a projection at a first location and said secondsidewall includes an indentation at a second location, said first andsecond locations being defined such that said projection of a first oneof said tanks is able to be inserted into said indentation of a secondone of said tanks when a plurality of said tanks are stacked on top ofeach other in a position external to said second chamber.
 8. The tankassembly of claim 1 further including a filler tube assembly positionedwithin said second aperture of said second chamber, said filler tubeassembly including a filler tube, a shroud, an outer housing, and areduction sleeve, said filler tube, shroud, outer housing, and reductionsleeve all adapted to be secured to each other without the use ofseparate fasteners.
 9. The tank assembly of claim 1 further including aplurality of fastener apertures defined in said perimeter wall aroundsaid second aperture, said plurality of fastener apertures being adaptedfor securing a filler tube assembly within said second aperture, andsaid plurality of fastener apertures being arranged in a non-symmetricalmanner such that said filler tube assembly can only be mounted withinsaid second aperture in a single orientation.
 10. The tank assembly ofclaim 1 further including a filler tube positioned within said secondaperture, said filler tube including an anti-siphon structure adapted tohinder a hose from being inserted through said filler tube and into saidtank.
 11. A tank assembly for storing urea solution comprising: a tankadapted to store urea solution, said tank comprising a first wallsidewall, a second sidewall, and a perimeter wall, said second sidewallspaced from said first sidewall, said first and second sidewalls eachgenerally defining a first and second plane, respectively, wherein saidfirst and second planes are parallel to each other, and said perimeterwall connecting said first and second sidewalls together; an indentationon said first wall having a first shape; and a projection on said secondwall having a second shape, said second shape substantially matchingsaid first shape such that said projection on a first one of said tanksmay be inserted into said indentation on a second one of said tanks whena plurality of said tanks are stacked on top of each other, whereby saidfirst tank resists movement of said second tank in any directionparallel to said first plane when said projection on said first tank isinserted into said indentation on said second tank.
 12. The tankassembly of claim 11 further including an aperture defined in saidperimeter wall for receiving an assembly and a plurality of fastenerapertures defined in said perimeter wall around said aperture, saidplurality of fastener apertures being adapted for securing the assemblywithin said aperture, and said plurality of fastener apertures beingarranged in a non-symmetrical manner such that said assembly can only bemounted within said aperture in a single orientation.
 13. The tankassembly of claim 12 wherein said assembly is one of a filler tubeassembly and a sensor assembly.
 14. The tank assembly of claim 11further including: an L-shaped bracket adapted to be secured to a motorvehicle; a plurality of side brackets adapted to be secured to saidL-shaped bracket; a strap adapted to be secured to said side brackets;and a recess defined in the perimeter wall of said tank, said recessshaped to receive a portion of said strap whereby said strap and saidrecess cooperate to secure said tank to said L-shaped bracket and saidside brackets.
 15. The tank assembly of claim 14 wherein said tank issecured to said L-shaped bracket and said side brackets without the useof any fastener that pierces any portion of said tank and any one ofsaid L-shaped bracket and said side brackets.
 16. The tank assembly ofclaim 14 further including; a metal hoop secured around said perimeterwall; a metal front cover secured to said metal hoop and positionedgenerally adjacent said first sidewall; a metal rear cover secured tosaid metal hoop and positioned generally adjacent said second sidewallwherein said metal hoop and said metal front and rear covers, incombination, define an enclosure in which said tank is positioned; andwherein said perimeter wall and said first and second sidewalls of saidtank are made of plastic.
 17. The tank assembly of 14 further includinga metal enclosure surrounding said tank, said metal enclosure includinga first part and a second part, said first part surrounding said firstsidewall and said perimeter wall of said tank, and said second partsurrounding said second sidewall of said tank.
 18. The tank assembly ofclaim 16 further including: a first spacer positioned between saidL-shaped bracket and a first one of said side brackets, said first sidebracket being secured to said L-shaped bracket by a first fastenerinserted through a first set of aligned holes in said first sidebracket, said first spacer, and said L-shaped bracket; and a secondspacer positioned between said L-shaped bracket and a second one of saidside brackets, wherein said second side bracket is secured to saidL-shaped bracket by a second fastener inserted through a second set ofaligned holes in said second side bracket, said second spacer, and saidL-shaped bracket
 19. The tank assembly of claim 11 further including: areservoir fluidly isolated from said tank; a sensing unit positionedadjacent an aperture adapted to receive a urea solution dispensingnozzle, said sensing unit adapted to detect a quality of the ureasolution dispensed from the nozzle; and a switch adapted to direct theurea solution to said reservoir if said sensing unit determines that thequality of the urea solution does not conform to a predeterminedstandard, said switch further adapted to allow the urea solution toenter the tank if said sensing unit determines the quality of the ureasolution does conform to the predetermined standard.
 20. The tankassembly of claim 11 further including an aperture defined in saidperimeter wall of said tank, and a filler tube positioned within saidaperture, said filler tube including an anti-siphon structure adapted tohinder a hose from being inserted through said filler tube and into saidtank.
 21. A tank assembly comprising: a tank adapted for storing ureasolution; an aperture defined within said tank for receiving ureasolution; a reservoir fluidly isolated from said tank; a sensing unitpositioned adjacent said aperture, said sensing unit adapted to detect aquality of the urea solution being delivered to the aperture; and aswitch adapted to direct the urea solution to said reservoir if saidsensing unit determines that the quality of the urea solution does notconform to a predetermined standard, said switch further adapted toallow the urea solution to enter the tank if said sensing unitdetermines the quality of the urea solution does conform to thepredetermined standard.
 22. The assembly of 21 wherein said tank furtherincludes: a plurality of fastener holes adapted to allow said tank to besecured to a diesel fuel tank; and a recess in a perimeter wall of saidtank, said recess shaped to receive a portion of a strap whereby a strapmay be used to secure the tank to a bracket for mounting to a vehicleframe; and wherein said tank and said reservoir are both defined by asingle structure made of molded plastic wherein said tank and saidreservoir share at least one wall.
 23. The assembly of claim 21 whereinsaid tank further includes: a first wall sidewall; a second sidewallspaced from said first sidewall, said first and second sidewalls eachgenerally defining a first and second plane, respectively, wherein saidfirst and second planes are parallel to each other; and a perimeter wallconnecting said first and second sidewalls together.
 24. The assembly ofclaim 23 further including: a metal hoop secured around said perimeterwall; a metal front cover secured to said metal hoop and positionedgenerally adjacent said first sidewall; and a metal rear cover securedto said metal hoop and positioned generally adjacent said secondsidewall wherein said metal hoop and said metal front and rear covers,in combination, define an enclosure in which said tank is positioned.25. The assembly of claim 23 further including a metal enclosuresurrounding said tank, said metal enclosure including a first part and asecond part, said first part surrounding said first sidewall and saidperimeter wall of said tank, and said second part surrounding saidsecond sidewall of said tank.
 26. The assembly of 24 further including:an L-shaped bracket adapted to be secured to a motor vehicle; aplurality of side brackets adapted to be secured to said L-shapedbracket; a strap adapted to be secured to said side brackets; and arecess defined in the perimeter wall of said tank, said recess shaped toreceive a portion of said strap whereby said strap and said recesscooperate to secure said tank to said L-shaped bracket and said sidebrackets.
 27. A tank assembly for storing urea solution comprising: atank adapted to store urea solution, said tank comprising a firstsidewall, a second sidewall, and a perimeter wall, said second sidewallspaced from said first sidewall, said first and second sidewalls eachgenerally defining a first and second plane, respectively, wherein saidfirst and second planes are parallel to each other, and said perimeterwall connecting said first and second sidewalls together; an L-shapedbracket adapted to be secured to a motor vehicle; a plurality of sidebrackets adapted to be secured to said L-shaped bracket; a strap adaptedto be secured to said side brackets; and a recess defined in theperimeter wall of said tank, said recess shaped to receive a portion ofsaid strap whereby said strap and said recess cooperate to secure saidtank to said L-shaped bracket and said side brackets.
 28. The assemblyof claim 27 further including: a metal hoop secured around saidperimeter wall; a metal front cover secured to said metal hoop andpositioned generally adjacent said first sidewall; and a metal rearcover secured to said metal hoop and positioned generally adjacent saidsecond sidewall wherein said metal hoop and said metal front and rearcovers, in combination, define an enclosure in which said tank ispositioned.
 29. The assembly of claim 27 further including a metalenclosure surrounding said tank, said metal enclosure including a firstpart and a second part, said first part surrounding said first sidewalland said perimeter wall of said tank, and said second part surroundingsaid second sidewall of said tank.
 30. The tank assembly of claim 27further including an aperture defined in said perimeter wall forreceiving a filler tube assembly and a plurality of fastener aperturesdefined in said perimeter wall around said aperture, said plurality offastener apertures being adapted for securing the filler tube assemblywithin said aperture, and said plurality of fastener apertures beingarranged in a non-symmetrical manner such that said filler tube assemblycan only be mounted within said aperture in a single orientation.